The 99p Avia quartz went back on its own band today.
When I cleaned up the watch initially, I put it on a new band, as the one it came on was a bit grubby, however the original is a very nice, fairly high quality band and suits the watch, so I gave it the leather cleaning treatment.
This consisted of steeping it in a mix of white vinegar some disinfectant and a little detergent, and giving it a good scrub with a toothbrush.
The initial cleaning solution was then replaced with fresh, and the band was left to soak for a few hours. This allowed the vinegar to "tenderize" the collagen in the leather gently, softening it up. Next it was dried on a radiator overnight, sandwiched between sheets of kitchen roll, and pressed flat with a couple of scraps of plywood, with a weight placed on top.
Finally the sued side was freshened up with a tiny amount of sued cleaner. Not enough to make it greasy, just enough to make it feel new. The top surface sheen was restotored with an equally tiny rubbing of silicon grease.
The result is a strap that looks like it just came out of the packet, and smells fresh and new.
This also frees up the replacement band for one of my Timex Automatics.
No need for having multiple sources to suffer parts size variations. Parts are made in batches afterwhich the same machine is reconfigured for another part or another step on the same batch. True in the old times of mechanical stops as well as in CNC of today. An error during reconfig, a larger tool wear there, temperature variations and you may be making parts significantly different. Very old watches were made practically by hand so to fit each part to another. Russians probably had decent machines but onerous production targets, impossible to impose strict tolerances so if the problem was correctable at assembly, so be it.